Wakoopa is very web2.0-ish site (both in name and functions) that provides users with a way to track their software usage (what apps and for how long). Exposing very local and personal things to whole Internet… Daring, isn't it?
Data is also gathered and made available online - from simple ratings to various widgets and api. For submitting data you have to register and install small tracking application (Win and Mac supported) that sends your stats every 15 minutes.
Site surfaced in spring 2007 (as far as I remember) and initial reaction from users was pretty much cold shower. People are naturally suspicious about parting with any personal data, but it's not like telling anyone what amount of time you spend browsing web is dangerous (at least not to your boss). :) Anyway site is still alive and has steady userbase - home page usually shows 20-30 thousands people with tracker enabled online.
What they got right? Wakoopa generates tons of interesting data and supplies tools to work with that. It gets data from users without making users work at it. Web 2.0 at its best.
What they got wrong? I think they got too personal. It's one thing to be curious what applications are popular and another to tell the world that you are actively contributing to World of Warcraft being in the top 10 most used. :)
I am very curious what is going to happen with Wakoopa in the future. :) It may not be huge social success but it is excellent concept that has lots of value to harvest.